Digoxin

Presentation

  • Symptomatology usually vague – toxicity usually d/t other illness -> AKI -> accumulation of renally cleared digoxin
  • GI symptoms (NVD) commonly precede cardiotoxicity
  • Color vision change/halo around lights are rare
  • Worth checking digoxin levels on pretty much any ED pt who is on digoxin
  • Some are toxic even at upper “normal” 2.0 ng/dl
  • Hyperkalemia – indication of severity of toxicity in acute overdose
  • EKG changes – accelerated junctional rhythm most common, classically w/ scooped STD
  • Therapeutic Dig level does not exclude toxicity

Treatment

  • Treatment usually supportive, IVF to address underlying AKI
  • Treat hyperkalemia
  • Draw dig level before starting antidote
  • Indications for reversal:
    • Hemodynamic instability
    • Electrical instability – ventricular dysrhythmias
    • Elevated K+ – marker of disease severity, accumulates extracellularly d/t poisoned K-Na ATP-ase

Dosing

  • Easy/modern version: 1 vial for chronic toxicity, 2 vials for acute – This is probably the way to go
  • Dose based (peds ingestion): 1 vial per 40 mcg of ingested digoxin
  • Old Dosing guidelines:
  • Formula based: ([serum dig] x wt in kg)/100 = number of vials
  • Formula cheat: [serum dig] = # vials  (e.g. this assumes a 100 kg pt)
  • Crashing patient: 20 vials (this will be more than all the vials in the hospital)